1. Field of Invention
The present invention relates to a fuel feeding system for a vehicle and, more particularly, to a fuel feeding system for a vehicle, which is capable of improving suction volumetric efficiency by using a subsidiary jet pump having a modified structure.
2. Description of Related Art
In a Gasoline Direction Injection (GDI) engine, a fuel feeding system that transports fuel from a fuel tank to an engine includes a fuel pump module that transports fuel stored in a fuel tank up to a preceding stage of a high pressure pump, the high pressure pump that increases the pressure of fuel, a fuel pressure rail that maintains a high pressure of fuel before fuel is injected into cylinders, and an injector that injects fuel into the cylinders.
In the fuel feeding system, an upstream portion up to the preceding stage of the high pressure pump is called Low Pressure Circuit (LPC). FIG. 1 is a diagram illustrating a portion of an LPC of a fuel feeding system, which is disposed in a fuel tank.
With reference to FIG. 1, the inside of a fuel tank 1 is equipped with a reservoir 2 that stores fuel for a predetermined period of time to stabilize supply of fuel, a fuel pump 3 that pumps out fuel to an engine by pressurizing the fuel, and a fuel filter 4 that filters out foreign matter contained in fuel which is sent to the fuel pump 3.
In addition, a jet pump 5 and an anti-siphon valve 6 are installed in the fuel tank 1. The jet pump 5 turns pressure energy into kinetic energy by causing a portion of fuel pressurized by the fuel pump 3 to pass through a small nozzle and makes surrounding fuel enter the reservoir 2 using negative pressure generated at this time. The anti-siphon valve 6 prevents fuel in the reservoir 2 from flowing out through the jet pump 5 when an engine is turned off.
There is also a pressure regulator 7 for maintaining a constant pressure of the fuel transported to an engine.
Typically, a rear end of the nozzle of the jet pump 5 is provided with a mixing chamber and an expanding tube to effectively create a predetermined pressure (negative pressure). A conventional fuel tank includes only one jet pump to pump fuel out of the fuel tank 1 into the reservoir 2.
Meanwhile, as illustrated in FIG. 2, a saddle fuel tank 10 uses two jet pumps 17 and 19. One of the two jet pumps transports fuel in a main chamber 11 to a reservoir 15 and the other transports fuel in a subsidiary chamber 13 to the main chamber 11.
The dual jet pump system has a disadvantage of low suction volumetric efficiency attributable to a long distance between the jet pumps and a suction pipe disposed in the subsidiary chamber.
In addition, the dual jet pump system is disadvantageous in that suction recovery speed is very low when the suction pipe in the subsidiary chamber is exposed to air and then becomes submerged, i.e., under the condition of a low flow rate of fuel.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.